Polymers with acrylic (acrylate, methacrylate, etc.) functionality are desirable because of the ease in which such polymers undergo free radical initiated additions which crosslink the resin or further polymerize it with unsaturated monomers. Among the well known applications of such polymers are anaerobic, UV, and two-component chemically cured adhesive systems as well as various coatings.
An especially desirable class of polymers in which grafted acrylic functionality is advantageous is the polyorganosiloxane group, commonly known as silicones. Silicone resins are well known for the desirable thermal, electrical and weather resistant properties.
In U.S. Pat. No. 3,577,264 to Nordstrom, there is described a radiation curable film forming paint formulation which employs a solution of vinyl monomers and an alpha-beta olefinically unsaturated siloxane formed by condensing a hydroxy acrylic ester with a siloxane having hydroxy or hydrocarbonoxy groups. The acrylate functionality is bound to the siloxane by a Si--O--C bond.
In U.S. Pat. No. 3,878,263 to Martin, there are described acrylate-functional polyorganosiloxanes which are prepared from acrylate or methacrylate functional silanes by equilibration with organopolysiloxanes. The methacrylate functional silanes reportedly may be prepared by hydrosilation of an acrylate or methacrylate ester of an unsaturated alcohol or by reaction of an appropriate chloroalkylsilane with a tertiary amine salt of acrylic or methacrylic acid.
In U.S. Pat. No. 4,035,355 to Baney et al., there are described anaerobically curing compositions which employ polysiloxane polymers in which acrylate groups are bonded to the polymer backbone by Si--C bonds. These polymers are also produced from organosilanes having both acrylate functionality and hydrolyzable functionality by equilibration. Other references relating to acrylate functional silicones include U.S. Pat. Nos. 2,793,223, 2,922,806, 2,956,044, 3,417,161 and 4,348,454 and U.K. Pat. Nos. 1323869 and 1384898.
Examples of other acrylic functional polymers include urethane-acrylate capped prepolymers as disclosed in U.S. Pat. Nos. 4,295,909 and 4,309,526 to Baccei, and the commercially available polyethylene glycol dimethacrylate (PEGMA). A commercially available butadiene polymer with terminal methacrylate groups is B. F. Goodrich VTBN.
In U.S. Pat. No. 4,139,519 there is described a method of grafting organosilicon groups, such as trimethylsiloxy or (trimethylsiloxy)dimethylsiloxy groups to butadiene polymers and copolymers to improve their viscosity and curing properties. The method involves hydrosilation of the butadiene double bonds with a SiH functional silane or siloxane.